Passive sensors and control algorithms for faucets and bathroom flushers

Abstract

An optical system includes one or several passive optical detectors sensitive to ambient (room) light for controlling, for example, the operation of automatic faucets or automatic bathroom flushers. The passive optical sensors provide signals to flow controllers, including control electronics and flow valves and require only very small amounts of electrical power for sensing users of bathroom facilities, and thus enable battery operation for many years. To control the operation of automatic faucets or automatic bathroom flushers based on ambient light, the controller executes novel algorithms.

The invention claimed is: 
     
       1. A system for controlling a valve of an electronic faucet or bathroom flusher, comprising:
 a first light detector optically coupled to a first input port and constructed to detect ambient light arriving to said first detector from a first field of view; 
 a second light detector optically coupled to a second input port and constructed to detect ambient light arriving to said second detector from a second field of view; and 
 a control circuit for controlling opening and closing of a flow valve, said control circuit being constructed to receive first data from said first light detector corresponding to the detected ambient light from said first field of view, and to receive second data from said second light detector corresponding to the detected ambient light from said second field of view, said control circuit being constructed to determine each said opening and closing of said flow valve based on a background level of said ambient light and a light level caused by a user targeted within one of said fields of view, said control circuit is further constructed to control said opening and closing by executing a detection algorithm detecting arrival of said targeted user and then detecting departure of said targeted user within one of said fields of view; said departure of said targeted user being detected by
 taking a derivative of said first data or taking a derivative of said second data, and 
 detecting two transition patterns in said derivative of said first data or said derivative of said second data, wherein said two transition patterns are separated by a time corresponding to said user being within one of said fields of view. 
 
 
     
     
       2. The system of  claim 1  wherein said control circuit is constructed to detect two asymmetrically positioned transition patterns corresponding to a level differential between said background level and said targeted user level. 
     
     
       3. The system of  claim 1  wherein said detection algorithm processes detection of an increase of ambient light in said fields of view due to the presence of the user. 
     
     
       4. The system of  claim 1  wherein said detection algorithm processes detection of a decrease of ambient light in said fields of view due to the presence of the user. 
     
     
       5. The system of  claim 1  wherein said detection algorithm processes detection of an increase of ambient light in one of said fields of view and detection of a decrease of ambient light in the other of said fields of view due to the presence of the user. 
     
     
       6. The system of  claim 1  wherein said determination is performed using a stochastic algorithm on optical data from said light detector. 
     
     
       7. The system of  claim 6  wherein said stochastic algorithm includes a Kalman filter. 
     
     
       8. The system of  claim 1  wherein said determination is performed using a predictive algorithm on optical data from said light detector. 
     
     
       9. A system for controlling a valve of an electronic faucet or bathroom flusher, comprising:
 a first light detector optically coupled to a first input port and constructed to detect ambient light arriving to said first detector from a first field of view; 
 a second light detector optically coupled to a second input port and constructed to detect ambient light arriving to said second detector from a second field of view; and 
 a control circuit for controlling opening and closing of a flow valve, said control circuit being constructed to receive first data from said first light detector corresponding to the detected ambient light from said first field of view, and to receive second data from said second light detector corresponding to the detected ambient light from said second field of view, said control circuit being constructed to determine each said opening and closing of said flow valve based on a background level of said ambient light and a light level caused by a user targeted within one of said fields of view, said control circuit is further constructed to control said opening and closing by executing a detection algorithm detecting arrival of said targeted user and then detecting departure of said targeted user within one of said fields of view; said departure of said targeted user being detected by
 taking a derivative of said first data or taking a derivative of said second data, and 
 detecting two transition patterns in said derivative of said first data or said derivative of said second data, having the same energy of transition. 
 
 
     
     
       10. The system of  claim 9  wherein said control circuit is constructed to detect two asymmetrically positioned transition patterns corresponding to a level differential between said background level and said targeted user level. 
     
     
       11. The system of  claim 9  wherein said detection algorithm processes detection of an increase of ambient light in said fields of view due to the presence of the user. 
     
     
       12. The system of  claim 9  wherein said detection algorithm processes detection of an increase of ambient light in one of said fields of view and detection of a decrease of ambient light in the other of said fields of view due to the presence of the user.